This invention relates in general to compressors and in particular to a new and useful device and method for detecting surges in turbocompressors.
The invention relates particularly to a method of detecting surges in turbocompressors similar to that disclosed in U.S. Pat. No. 2,929,547.
A process in a turbocompressor in which the pumped medium flows from the compression side back to the suction side periodically, is called surge. This process takes place in operating states of too great a compression ratio between outlet and inlet pressures, or, of too low a throughput volume. Since the pumped medium heats up due to the compression in the compressor, the pumped medium flowing back during a surge is also hotter than the aspirated medium so that a surge results in a change of the temperature conditions at the compressor intake. The change in temperature may be utilized as an indicator of the presence of a surge to trigger measures for the elimination of the surge, e.g. the opening of a blow-off valve.
At 0.5 to 2 seconds, the pumping cycle of a compressor is relatively short. It is difficult to detect these short temperature changes with conventional temperature sensors. In addition, the daily and seasonal temperature fluctuations of the aspirated air mean an interference in air compressors, or the process related aspiration temperature fluctuations in gas compressors. In compressors with intermediate cooling, the coolant temperature and quantity wield an influence. All of these interfering influences may lead to the surges not being detected quickly enough or, when operating conditions change, not reliably enough, for which reason the countermeasures are also either not triggered at all or are triggered too late.